Multistage energy-converting device



'Margh 3, 1910 v w. E. GATLIN MULTISTAGE ENERGY-0"VERTING DEVICE F118d NOV- 20. 1967 2 Sheets-Shed 3 arm Wax/441A.

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March 3, 1970 w. E. GATLIN MULTISTAGE ENERGY-CONVERTING DEVICE 2 Sheets-Sheet 2 Filed Nov. 20, 1967 United States Patent US. CI. 9187 9 Claims ABSTRACT OF THE DISCLOSURE A multistage energy-converting device including a housing, two counter-rotating rotors having power disks formed thereon with lobes and recesses formed on their peripheries which mesh with one another, a first-stage inlet portion which is periodically opened by the recess on one of the power disks to feed expandable fluid to a first expansion stage, an open first-stage outlet to feed partially expanded fluid to a second expansion stage where the fluid is further expanded and then exhausted through an outlet port, and a bypass formed in the surface of the chambers to equalize fluid pressure during critical stages of operation.

This invention relates generally to positive-displacement, rotary-type, energy-converting devices, and relates more specifically to multistage, counter-rotating rotor-type piston, energy-converting devices.

Various types of multistage, energy-converting devices have been developed in which a work fluid is sequentially transferred from one stage work chamber to another stage work chamber in order to increase the operating efficiency of the devices. While fluid was in each stage, energy available therefrom was converted to mechanical work, such as rotary motion, by the device.

It is an object of this invention to provide improvements in positive-displacement, multiple-stage, counter-rotating rotor-type energy-converting devices of the above type.

Another object is to provide a multiple-stage rotary device of the above type which can be easily fabricated and assembled and is versatile in its mode of operation.

Still another objective is to provide an energy-converting device which has the advantages of dynamic balance, efiiciency, a low number of moving parts, mechanical simplicity, and reliability.

Yet another object is to provide a rotary device of the above type having improved fluid transfer operation and valving operation.

The above and other objectives can be attained by a rotary, positive-displacement engine having a bore of two cylindrical chambers formed therein which enclose two side-by-side, counter-rotating rotors. Each rotor has power disk portions formed thereon which define, in cooperation with each other and the chamber walls, two secondstage expansion chambers, and a first-stage expansion chamber which is located parallel to and between the two second-stage expansion chambers. The expansion chambers are further defined by the peripheral surfaces of the power disks and the lobes and recesses formed thereon and by housing end walls. When the two rotors are counter rotating on a one-to-one basis, the lobes of one rotor will mesh with the recessed portions of the other rotor. The side wall of the first-stage power disk and the recessed portions provide the valving action for expandable fluid inlet into the first stage for a first stage of expansion. The chamber wall is formed with a cutout above the first-stage inlet port to allow fluid flow between the two sides of the expansion chambers toward the end of the expansion cycle. In operation, the cutout is sealed by the crown of the lobe and the chamber wall at the end of the cycle, whereupon a new cycle begins. At the end of the firststage expansion, the partially expanded fluid is entrapped between the chamber wall, the lobes, and the rotor, wherein it is rotatively transferred to an angular position at which it can be released through a very short transfer passageway, with low free expansion, to the two outermost second-stage expansion chambers wherein the fluid is further expanded. Thereafter, the substantially fully expanded fluid is exhausted from the device.

Other objectives, features, and advantages of this invention will become apparent upon reading the following description and referring to the accompanying drawings in which:

FIG. 1 is an exploded perspective view of the positivedisplacement, rotary-type, energy-converting device incorporating the features of this invention;

FIGS. 2a-2c are schematic diagrams of the first stage taken through a cross-sectional plane perpendicular to the axis of rotation of the rotors illustrating the first-stage operation of the device;

FIGS. 3a-3c are schematic diagrams of the first and second stages taken through planes, perpendicular to the axis of rotation illustrating the relationship between the first stage and a second stage; and

FIG. 4 is a cross-sectional view again taken through the rotor illustrating a second embodiment of the recessed portions on the power disks.

Referring now to the details of the embodiments, FIG. 1 illustrates a positive-displacement, rotary-type, energyconverting device having a housing 12, which is adapted to receive two end plates 14 and 16. The interior surface of the housing 12 is formed into a bore of two contiguous conjoined bores 18 and 20 of generally cylindrical wall contour which receive rotors 22 and 24, respectively. In addition to the rotors, the side-by-side contiguous and conjoined bores 18 and 20 receive inner casings 26, 28, and 30 which, when bolted together, separate and seal a centrally located first-stage expansion chamber from two outer adjacent second-stage expansion chambers.

Referring now to the device in more detail, the inner casings 26, 28, and 30 are assembled and bolted together by bolts 32 which extend through holes in the inner casings 26 and 30 and are threaded into the bolt-receiving bores 34 in the inner casing 28. When assembled, the casings 26, 28, and 30 have inner circular grooves 36'and 38 formed outward from the cylindrical bearing surfaces thereof which are adapted to rotatably enclose first-stage power disks 40 and 42 formed on the rotors 22 and 24, respectively.

The first-stage expansion chamber is formed by the close fitting cooperation of the walls of the grooves 36 and 38 with the centrally located power disks 40 and 42 of rotors 22 and 24, respectively. These power disks 40 and 42 each have diametrically opposed lobes 44 and 46 and adjacent recessed portions 48 and 50 formed on small segments of their respective peripheral surfaces. The lobes 44 and 46 of rotors 22 and 24, respectively, are operable to define the angular limit of the first-stage expansion chambers.

As will be explained in more detail with reference to the following figures, when the rotors 22 and 24 are counter rotating, the lobes 44 of rotor 22 mesh with recessed portions 50 of rotor 24 while the lobes 46 of rotor 24 mesh with the recessed portions 48 of rotor 22.

A fluid is transferred into a first-stage expansion chamber through an inlet passageway 52 formed through the housing 12, an inlet passageway 54 formed through the inner casing 28 aligned therewith, and through the side wall of grooves 38 at a first-stage inlet port (FIG. 2a) which is periodically uncovered by the recessed portion 50. Thus, the recessed portion 50, and the side wall of the power disk 42 provide the inlet valve operation for the first-stage expansion chamber, as will be explained in more detail shortly with reference to FIGS. 2a-2c.

Referring now to the features of the second-stage expansion chambers, the outer side walls 56 of the assembled inner casings 26, 28, and 30 abut the inner side walls of two power disks 58 associated with rotor 22 and two power disks 62 associated with rotor 24. The power disks 58 and 62 associated with the second-stage expansion chambers can, if desired, be made thicker than the power disks 40 and 42 associated with the first-stage expansion chamber. In any event, power disks 58 and 62 each includes, respectively, two diametrically opposed lobes 66 and 68, and their adjacent diametrically opposed recesses 70 and 72. The diametrically opposite lobes 68 and the adjacent diametrically opposed recesses 72 of rotor 24 are operable to mesh with the recesses 70 and the lobes 66, respectively, of the rotor 22 (FIGS. 3a-3c) when the two rotors are abutting one another and are counter rotating on a one-to-one ratio. The walls of the second-stage expansion chambers are formed by the outer wall 56 of the inner casings 26, 28, and 30, the cylindrical chamber walls of the contiguous bores 18 and 20 formed in the housing 12, and the side walls of the end plates 14 and 16, when the units are assembled. The lobes on the power disks 58 and power disks 62 also define the angular limits of the second-stage expansion chambers.

As will be explained in more detail with reference to FIGS. 3a-3c, partially expanded fluid from the first-stage expansion chamber is transferred to the second-stage expansion chamber by means of fluid transfer passageways 82 formed in the inner casing 28. In operation, the expandable fluid flows upward from the first-stage outlet ports 114 in the side walls of the grooves 36 and 38 (FIGS. 2a-2c) and outward to the second-stage inlet ports 84 located adjacent the side wall of the lobes 68 of the second-stage power disks 62. This passageway is very short, thereby having the advantage that little energy is lost through needless free expansion of the fluid when transferred from the first stage to the second stage. After a second stage of expansion, the fully expanded fluid is exhausted from the second-stage expansion chamber through outlet ports 88 and 90 formed through the bottom wall of the housing 12.

Each rotor 22 or 24 is a single piece of material, such as stainless steel, which is machined to close tolerances so that no seals are required for the power disks, such as 40 and 58 of rotor 22 and the adjacent lobes and recessed portions formed thereon. The lobes and recessed portions on the power disks are generally circular with the exception that the crowns of the lobes on rotor 24 are clipped to the radius of the groove 36 and the bore wall 18, respectively, so that they are parallel to the cylindrical surface of the groove wall and the chamber wall. As a result, the crowns will seal with the cylindrical chamber walls after less angular rotation than if the crowns were left circular whereupon the expansion chambers have a smaller initial volume to thus provide an increase in the expansion ratio. The lobes and recessed portions associated with the first stage can be thinner, if desired, and of a smaller radius, and are angularly displaced from the lobes and recessed portions of the power disks 58 and 62 associated with the second stage. As a result of this configuration, the rotor can be readily machined from a single piece of material.

When assembled, the two rotors are synchronized to operate in counter rotation and complementary fashion on a one-to-one ratio by means of gears 92 and 94 secured to splined shafts 96 and 98 on both ends of the rotors 22 and 24, respectively. The splined shafts 96 and 98 project through apertures 100 and recesses 102 formed in the end walls 14 and 16 when assembled. Bearings 104 are slipped over the rotor shafts past the splined portions 96 and 98 to the smooth portion. Thereafter, the two inter-meshing gear pairs 92 and 94 are fitted onto the spline shaft 96 and secured thereon by washers 106, which form an end cap, and bolts 108, which are threadably fastened in threaded bores 110 in the end of the rotors 22 and 24. Power can be taken off of either gear on either end of the device so that either direction of rotation is obtainable.

Additional reference is made to the end plates 14 and 16, which include grooves 112 formed in the inside face extending radially from the apertures to permit release of steam pressure at the bearing.

Referring now to the operating Rankine cycle of the positive-displacement, counter-rotating type, energy-converting device, reference is made to FIG. 2a, wherein a first-stage expansion chamber--just prior to the inlet cycleis illustrated in schematic cross-sectional View taken through a plane normal to the axis of rotation of the power disks. The side inlet ports are radially displaced relative to the axis of rotation so that walls of the centrally located power disk 42 normally cover the first-stage inlet ports 110 in either side of the first-stage expansion chamber, substantially sealing inlet of the expandable fluid or working fluid except for slight leakage through the interface thereat. As the power disks 40 and 42 counter rotate in the direction of the arrows, the first-stage inlet port 110 is radially positioned and angularly displaced to one side of the abutment between disks so that it is uncovered by the recessed portion 50 adjacent to lobe 46, as indicated in FIG. 2b, thereby permitting expandable fluid to enter the initial volume 110 of the expansion chamber during this small sector of rotation that the recessed portion 50 is in registry with the inlet port 110. As the fluid enters the initial volume 111, it exerts a force against lobes 46 and 44 in the direction of increasing volume 111. As a result, the power disks 40 and 42 are further rotated in the direction of the arrows until eventually, the firststage inlet port 110 is again covered by the side wall of power disk 42, as illustrated in FIG. 26. The entrapped pressurized steam in volume 111 begins expanding and exerts a force against the lobes 44 and 46, causing the two power disks 40 and 42 to further rotate in the direction of the arrows. Eventually, the power disks 40 and 42 will rotate through degrees and the originally diametrically opposite lobes 44 and 46 and recesses 48 and 50 will be in the relative positions indicated in FIG. 2'a. Thereafter, additional pressurized fluid will be fed to the initial volume of the expansion chamber and added to the residual partially expanded fluid contained therein. During the cycle, the relatively smooth, uninterrupted surfaces of the power disks offer little impediment to fluid flow, thereby improving efficiency.

In order to equalize fluid pressure between the two sections of the expansion chamber toward the end of an expansion cycle when the lobes 44 and 46 rotate toward sealing off one part of the expansion chamber adjacent the leading side of the lobe 46 from further expansion while the other part of the expansion chamber adjacent the trailing edge of the lobe 44 continues to expand, a cutout 112 is formed in the cylindrical wall of groove 38 of the inner casing 28. In this manner, a certain amount of fluid bypass is allowed to pass over the crown of lobe 46 until the position shown in FIG. 2a is reached and the inlet port 110 is ready to open. At the time the inlet port 110 is ready to open, the crown of lobe 46 is just sealing with the cylindrical portion of the groove wall 38 and the clipped crown of lobe 44 is just sealing with the other cylindrical portion of the groove wall 36, whereupon, the small initial volume 111 is sealed.

The partially expanded fluid entrapped in the volume 111 between the lobes 44 of power disk 40 and the lobes 46 of power disk 42 is rotatively transferred part of the way around the grooves 36 and 38 to an outlet port 114 angularly displaced on the other side of the abutment or contact between disks where it can be exhausted from the first stage into the second stage. This outlet port 114 is always open so that, as the lobes 44 and 46 progressively rotate, as illustrated in FIGS. 2a2c, the entrapped, partially expanded fluid is forced out through the first-stage outlet port 114 from a position on one side of the abutting portions of the power disks 40 and 42, up through the short narrow transfer passage 82 (FIG. 1) and outward to the inlet ports 84 of the two second-stage expansion chambers at a location on the other side of the abutting portions of the power disks 58 and 60. Thus, free expansion during transfer between stages is significantly low.

Referring now to the second-stage expansion chambers and their relationship to the first-stage expansion chamber, reference is made to FIGS. 3a-3c, wherein progressive stagesof operation of one of the identical secondstage expansion chambers is illustrated schematically. For purposes of clarity in illustration, the rotors 22 and 24 are illustrated schematically by a dashed line, while the short first-stage transfer passage 82 is illustrated with an exaggerated elongation. It should, of course, be understood that the distances between the first stage and the second stage are generally those distances illustrated in FIG. 1.

When partially expanded fluid enters the second stage illustrated in FIGS. 3a-3c, the rotors 22 and 24 can be in the same relative position that the firstand the secondstage power disks were shown in FIG. 3a. For instance, the lower lobes 44 and 46 on the first-stage power disks 40 and 42 will just rotatively break their seal with the cylindrical groove walls 36 and 38, respectively, as the clipped lobe-66 on the second-stage power disk 58 is rotated into contact with the cylindrical portion of the chamber wall 18 just beyond bypass 112 and lobe 68 of power disk 62 seals with the cylindrical chamber wall 20. Thus, the volumes 115 available at the ends of the transfer passageway 82, as defined by the bore walls 18, the end plates 14 and 16, and the peripheral surface of the' power disks on the rotors 22 and 24 are at a minimum just at fluid transfer. Thereafter, the transferred fluid expands, exerting a force on the lobes 66 and 68 of power disks 52 and 62, respectively, causing the rotors 22 and 24 to 'be counter rotated in the direction of the arrows, resulting in an increase in the volume 115 of the second-stage expansion chamber, as illustrated in FIGS. 3a3c, thereby producing work. This expansion continues until a position corresponding to 180 of rotation from the position illustrated in FIG. 3a is attained, the power disks are in the same relative position illustrated in FIG. 3a, whereupon, one cycle of expansion in the second-stage ends and a new cycle is about to begin. As the lobes 66 and 68 progressively rotate from the position illustrated in FIG. 3a, the lobes 66 and 68 rotate past the second-stage exhaust ports 88 and 90, thereby permitting the fully expanded steam to be exhausted from the device. It should of course be understood that the principles embodied within the device are not limited to two stages but are applicable to two or more expansion stages.

If the energy-converting device is used in a closed cycle system, the isentropic expansion will, at partial throttle, result in a temperature drop at the exhaust which is lower than the temperature of the fluid at the condenser. It follows that the pressure at exhaust is lower than the pressure at the condenser, and the fluid must be recompressed. As a result, when the engine is operating at partial throttle, the temperature and pressure at the exhaust should drop considerably from full throttle conditions, thereby helping to compensate for decrease in operating efliciency due to throttling.

Although the recesses are all illustrated as being generally cylindrically concave, it would be possible, as illustrated in FIG. 4, to make the valley of those recesses which mesh with the lobes having the clipped crowns somewhat convex rather than concave. As a result, the

initial volume of the expansion chamber will be further reduced, whereupon, the expansion ratio will be further increased.

Although the energy-converting device can operate as a steam engine, it should be understood that it is not by any means limited to this medium, but can operate on any expandable fluids including, for example, but not limited to, gas, or vapors.

In addition, this device operates on a reversible thermodynamic cycle and thus may be operated as a refrigerator or .on a compressor cycle.

Since the rotors are mechanically symmetrical about their axes and are thus balanced when they are counter rotating on a one-to-one ratio, they will have the same moment of inertia. Thus, when the angular velocities of the rotors vary, no torque reaction will be developed. In addition, gyroscopic action of the device will be counteracted internally. Consequently, the device could be utilized in delicately balanced systems where a torque reaction could otherwise produce an unwanted spin or gyroscopic action would exert a raction force perpendicular to an applied force.

While salient features have been illustrated and described with respect to a particular embodiment, it should be readily apparent that modifications can be made within the spirit and scope of the invention, and it is therefore not desired to limit the invention to the exact details shown and described.

What is claimed is:

1. An energy converting device comprising:

a housing having chambers formed therein;

two parallel cooperating rotors rotatively mounted in the chambers of said housing, said rotors each having a plurality of parallel axially displaced power disks disposed thereon, said power disks each having two pairs of generally adjacent lobes and recessed portions, each pair being diametrically opposite the other pair formed on minor segments thereof, said lobes and recessed portions of each power disk being operable to rotatively mesh with the recessed portions and lobes, respectively, of the other abutting power disk on the other said rotor; first means for forming a first stage expansion chamber associated with a first meshing pair of said power disks, and second-stage expansion chamber means associated with at least a second pair of meshing power disks, said expansion chambers each being two generally cylindrical conjoined chambers; means connected to counter rotate said rotors in synchronism with one another; first inlet port means in the wall of said expansion chamber being positioned a radial distance from the axis of rotation of one of said disks to be in registry with the path of rotation of said recessed portion, and being angularly displaced near a first side of the abutting portions between said disks, said port being operable to feed an expandable fluid to a volume of said first expansion chamber when uncovered by said recessed portions on a first meshing pair of said power disks, the fluid being operable during expansion to force rotation of the first meshing pair of power disks;

transfer means disposed in said first means for transferring the partially expanded fluid from the first stage expansion chamber to the second stage expansion chamber after a predetermined amount of power disk rotation, said transfer means including a first stage outlet port coupled in fluid communication with said first stage expansion chamber angularly displaced slightly from the other side of the abut ting portions between said disks, and a second stage inlet port coupled in fluid communications with a volume of the second stage expansion chamber at the first side of the abutting portions between said disks, the partially expanded fluid transferred into the second stage expansion chamber being operable during expansion to force rotation of the second meshing pair of power disks; and exhaust ports position, whereupon, after a predetermined amount of power disk rotation, the expanded fluid is exhausted from the device.

2. The energy-converting device of claim 1 in which said second-stage expansion chamber means includes at least two second-stage expansion chambers associated therewith, one of said second-stage expansion chambers being positioned axially relative to said rotors on one side of said first-stage expansion chamber and the other of said second-stage expansion chambers being so positioned axially on the other side of said first-stage expansion chamber; and a first pair and a second pair of said power disks rotatably positioned in said first and said second second-stage expansion chambers respectively.

3. The energy-converting device of claim 1 in which the wall forming one of said chambers is further formed with a cutout portion angularly positioned to prevent a lobe .of one of said disks from sealing with the generally cylindrical portion of said chamber to form an initial volume until said first stage inlet port is to open and a lobe of said other abutting disk is to seal with the generally cylindrical said chamber.

4. The energy-converting device of claim 2 in which said means for transferring a partially expanded fluid from the first-stage to the second-stage is a passageway through said first means, the inlet port thereto being continuously open.

5. The energy-converting device of claim 2 in which the lobes and recessed portions of said power disks associated with said first expansion chamber are angularly displaced from the lobes and recessed portions of said power disks associated with said second expansion chamher.

6. The energy-converting device of claim 1 in which said lobes on said power disks of one of said rotors are all clipped to a curvature of the radius of the cylindrical said chamber for sealing therewith for providing a small initial expansion chamber volume.

7. The energy-converting device of claim 3 in which said lobes on said power disks of one of said rotors are 8 all clipped to a curvature of a radius of the cylindrical said chamber for sealing therewith for providing a small initial expansion chamber volume.

8. The energy-converting device of claim 2 in which the wall forming one of said chambers is further formed with a cutout portion angularly positioned to prevent the lobe of one of said disks from sealing with the generally cylindrically portion of said chamber to form an initial expansion chamber volume until said first stage inlet port is to open and a lobe of said other abutting disk is to seal with the generally cylindrical said chamber.

9. The energy-converting device of claim 4 in which the wall forming one of said chambers is further formed with a cutout portion angularly positioned to prevent the lobes of one of said disks from sealing with the generally cylindrical portion of said expansion chamber to form an initial expansion chamber volume until said first-stage inlet port is to open and a lobe of said other abutting disks is to seal with the generally cylindrical said chamber.

References Cited UNITED STATES PATENTS 53,915 4/1866 Behrens 9187 893,485 7/ 1908 Grindrod 91-81 1,009,874 11/1911 Wentzel 70 1,052,124 2/1913 Berger 91-81 1,086,159 2/ 19 14 Goldberg. 2,101,676 12/ 1937 Guilhauman 6070 2,861,195 11/1958 Salzer 6070 XR FOREIGN PATENTS 15,140 11/1887 Great Britain. 90,666 6/ 1961 Denmark.

MARTIN P. SCHWADRON, Primary Examiner ROBERT R. BUNEVICH, Assistant Examiner US. Cl. X.R. 60-70; 91-81 

